Archive for Peterson Reference Guide to Sparrows
We’ve been a bit far north these past couple of weeks to have a real chance at green-tailed towhees, but we’ve been keeping eyes and ears open just in case one of those lovely sparrows — some say the loveliest — should happen to “overshoot” on its way to the breeding grounds.
As yesterday’s entry here pointed out, the generic affinities of the species were matter for discussion and debate for a long time. Beyond that question, though, there was another, more material: For twenty years after the species’ first description, we just didn’t know exactly what a green-tailed towhee was.
The species was first published by Audubon, as the green-tailed sparrow, in the last volume of the Ornithological Biography. Audubon never saw the bird himself, and never painted it; he bases his description of this “true Fringilla” instead on what seem to be two separate letters from John K. Townsend, who shot a “new and singularly marked Sparrow” on July 12, 1834. Townsend informed Audubon that
the specimen is, however, unfortunately young, and the plumage is not fully developed. I feel in great hopes of finding the adult….
In what appears to have been a subsequent letter, Townsend is forced to report that
In this I was, however, disappointed: I never saw it afterwards.
In fact, it was not until September 1842 that the towhee seems to have been encountered again — encountered, but not recognized. Somewhere in the Rockies, “about half way between New Mexico and the Colorado of the west,” William Gambel collected a single male of a bird that he named Fringilla Blandingiana, in honor of the discoverer of the turtle. Gambel was almost certainly aware of Audubon’s publication of the green-tailed towhee, but his bird, unlike Audubon’s, was an adult, and neither Gambel nor his colleagues at the Philadelphia Academy put the two together.
Six years later, in 1848, Baron de Lafresnaye received an adult bird in a shipment of Mexican and South American specimens sent by a M. Salé to his mother. Obviously unaware of Gambel’s description, and apparently likewise failing to compare it to Audubon’s, Lafresnaye described this “touit à coiffe rousse” as a new species, Pipilo rufo-pileus — thus assigning the species for the first time to the genus Pipilo.
It did not help that the original Townsend/Audubon specimen had somehow slipped into obscurity. John Cassin in 1855 asserted expressis verbis that there had never been such a skin — in spite of Townsend’s clear claim to have taken the specimen.
It would take a few years to figure it all out, but clarity shone forth with the publication in 1859 of the ornithological volume of the Pacific railroad surveys. While Spencer Baird was still using the name blandingiana in 1852, seven years later he, with Cassin and George Lawrence, was able to determine that blandingiana and rufopileus were mere synonyms of the Audubonian chlorurus.
And they were able to do so because the Townsend specimen had turned up — in Baird’s own cabinet, whence it passed into the collections of the Smithsonian as number 1896. Comparison of that skin with a slightly older male specimen and a series of adults led them to conclude that the Townsend skin
is unmistakeably the Pipilo here described, and settles the question in favor of the priority of the name chlorurus.
The odd outlier aside (Ridgway cites blandingiana as late as 1868), that has been the bird’s specific epithet ever since. And if anyone doubts that it should be so, Townsend’s bird from July 1834 still lies peaceful on its back in Washington.
Yes, I’m grateful that the bitter cup of whatever last week’s blizzard was named passed us more or less by. But that doesn’t make the dribs and drabs of powdery snow — an inch here, two inches there — we’ve been getting any more enjoyable.
Until this morning, that is, when the weather brought a sweet little field sparrow to the feeders.
A cool day in late November — especially a cool day in late November with cold and big snows predicted for the next day — is perfect for spending a little time with the backyard sparrows. The roster Tuesday morning was pretty much what was expected in northern New Jersey: lots of slate-colored juncos and white-throated sparrows, with the odd chipping, song, and fox sparrow to liven things up.
One bird, this bird, stood out in the feeder flock.
It was more than superficially junco-like, with a dull gray hood, white belly, and pink bill, but the pattern and color of the underparts were off. The dull olive-tan of the breast sides and flanks seemed wrong for not just for a slate-colored but for any junco, and the color reached quite far in towards the vent in a wide band, almost isolating the white undertail coverts. At some angles, the bird seemed to show a “color corner” between the hood and the breast sides, but at others just the usual smudgy blend shown by brown, immature or female, slate-colored juncos. Some of the rear flank feathers seemed to have very fine, just barely visible dark shaft streaks.
A closer look revealed a couple of other oddities. The ground color of the back seemed unexceptional, but its neat pattern of prominent but fine black streaks was worth a second look.
A bit of faint, diffuse streaking isn’t all that unusual in brown juncos this time of year, but these markings — darker in life than in the photos I took through my dirty window — struck me as beyond the pale.
I have no good, tightly-focused images of the wing pattern, but the one above at least gives a hint of the inconspicuous dotted wing bars; the tips of the median coverts weren’t always even this visible, but several of the greaters on each wing showed very small white triangular tips, creating a short, jagged “droplet” wing bar on the gray wing.
The bird’s tertials seemed more or less normal, with the typical broad buffy edgings of brown slate-colored juncos, if perhaps just a little more white towards the tip of the outer web than most.
While the other juncos were setting off their feathered flash bulbs all around the yard, this bird kept its tail resolutely folded. Though I could never contort myself into a position from which I could see the underside of the tail, I eventually had several reasonable if brief looks at the bird in flight, when it showed no white in the outer rectrices. Given my split-second view of the bird as it dashed into the arborvitae, I’d be hard pressed to prove that it actually even had all of its rectrices, but the ones I could see were dark.
With the growing suspicion that this might be a bird of mixed ancestry (put that way, which bird is not?), I worked hard to imagine the shadow of a face or throat pattern. The hood seemed unremarkably gray, with some dull rusty shading and streaking at some angles. There was an occasionally noticeable paler patch on each side of the neck beneath the auriculars, a feature shown by many brown slate-colored juncos.
The strangest thing about the bird’s head plumage was the area around the eye. The lore was decidedly blacker than the rest of the already dark head, no big deal in a slate-colored junco, but that color continued back to surround the eye and to end in an odd broad point behind it.
The bird was minutely larger than some of the other juncos in the flock, but still obviously much smaller than the white-throated sparrows.
If this is not just an even weirder than usual junco, what might it be? There are numerous records and reports of apparent hybrids between slate-colored juncos and white-throated sparrows, among them the winter birds well photographed and well described by Mark Szantyr a few years ago in Connecticut.
Nearly all of the documented individuals assigned to this hybrid combination are obviously, conspicuously intermediate in appearance, combining a white throat and lore with a gray breast and head. Some are more subtly marked, such as the one photographed by Szantyr and almost entirely junco-like but for a single brown, white-tipped greater covert. And surely others, perhaps the majority of them, are even more cryptically clad, indiscernible to humans and maybe even to their flock mates.
If in fact this odd sparrow was a hybrid or introgressant, I’m not sure we can tell with any real certainty which species might be lurking in its family tree. To my eye, the very fine back pattern and incomplete vent strap immediately suggested not a Zonotrichia but rather a Lincoln’s sparrow, but we will probably never know.
We’ll probably never know. But it’s always fun to look close; if it weren’t, we wouldn’t bother looking at all.
Both photographed here in northern New Jersey on the same late October day.
The calendar and the weather agree: It’s still late summer in northern New Jersey. A month from now, things will be different, but for the moment, only the most foolishly impatient prodder of the seasons is thinking of winter birds.
Except, of course, on this date. It’s September 6. And every year on this day, we pause — don’t we? — to remember the only Oregon junco named for a New Jersey birder.
Eugene Carleton Thurber died in California on September 6, 1896, at the shockingly tender age of 31. Born in Poughkeepsie in 1865, Thurber moved to Morristown in 1881; a “promising young ornithologist, a careful collector, and a good observer,” he published his magnum (and perhaps solum) opus in November 1887, the List of Birds of Morris County, notable especially for its early records of the Lawrence’s and Brewster’s warblers.
Fragile health sent Thurber to California in 1889, where he
lived an out-of-door life in the field, collecting birds and mammals, as his health would permit, and preserving to the end his love for his favorite study.
On May 24, 1890, Thurber collected two juncos on Mount Wilson in the San Gabriel Mountains. That summer, he showed the skins to Alfred Webster Anthony, another New York native exploring the Golden State; Anthony was “considerably surprised” to learn of juncos’
nesting in abundance within twenty-five miles of Los Angeles,
and as none of the other local collections seemed to include any similar specimens, he organized an expedition in late August to “obtain, if possible, a series of birds.” On August 27 and 28, Anthony found juncos “very abundant” between 5200 and 5800 feet elevation. He shot what seems to have been a total of eight adults, two juveniles, and one bird of unknown age and sex; all of those new adult specimens, however, were — as one might have predicted, without climbing the mountain in the first place — “in ragged moulting plumage,” inadequate for diagnosis.
So Anthony, apparently forgetting about Google Images, sent his little series, which by now included both of Thurber’s skins, to Washington, whence Robert Ridgway replied with some “rather unexpected” information: Anthony’s — Thurber’s — California juncos represented a “strongly marked” but still unnamed subspecies.
A deficiency, naturally enough, that Anthony promptly made up in the October 31, 1890, issue of Zoe:
I take pleasure in naming this handsome Junco for the discoverer, Mr. E.C. Thurber of Alhambra, Cal.
A few months later, having run through the juncos in a collection of birds purchased from Thurber in 1889, Frank Chapman was mildly skeptical: he pointed out that Anthony had failed to demonstrate that his new thurberi could be distinguished from the very widespread shufeldti.
The AOU, however, recognized the new race in 1892, and continued to list it as valid in the last Check-list to tally subspecies. BNA and Pyle, too, list thurberi among the Oregon junco subspecies. I’m glad we have a name for this population, whose recent colonization of the nearby California lowlands has provided some surprising insights into the rapidity of junco evolution.
Thurber’s early death kept him from leaving much of a biographical trail: We know a great deal more about the junco than the man. All the more reason to remember him once a year, I think, even if our juncos are still a month away.